Problem with Domino Blocks

I'm trying to create a mod based on domino art, and there is this one block that I don't know how to fix.

The relay block, when activated, should instantly activate adjacent relays.

Also, it is supposed to directly cause only adjacent domino blocks to fall.

However, I'm finding that the relay block not only causes domino blocks around it to fall, but it causes every single domino after it to fall at once.

If the block at x, y-1, z is a domino, the block at x-1, y, z is a domino, the block at x+1, y, z is a domino, the block at x, y, z-1 is a domino, or the block at x, y, z+1 is a domino,
Or if the block at x, y-1, z is an active relay, the block at x, y+1, z is an active relay, the block at x-1, y, z is an active relay, the block at x+1, y, z is an active relay, the block at x, y, z-1 is an active relay, or the block at x, y, z+1 is an active relay,
If the block at x, y, z is an inactive relay, then remove the block at x, y, z and place the active relay at x, y, z,
Else if the block at x, y, z is a domino of a certain color, then remove the block at x, y, z and place the falling domino of the same color at x, y, z.

Help?